Many electronic control systems in a vehicle use the throttle valve angle as a control signal. For example, an electronic throttle control uses it for a position feedback control of the butterfly valve, and a Motronic system uses it for control of fuel injection, ignition timing and in certain cases of exhaust gas recirculation. Another example is an electronic transmission control which uses a throttle valve angle to detect when to shift gears. As a result there may be a plurality of control units each requiring access to a butterfly valve angular position signal.
When, for cost reasons, only one throttle valve angle sensor is supposed to be read by more than one control unit, problems arise particularly with analog signals, and the magnitude of the signal may suffer and may not be present with the same accuracy in all control units. Variations may arise from manufacturing tolerances in components and from random operating variables such as stray voltages. Such variations can result in the fact that only one electronic control unit (ECU) can sense the throttle angle with sufficient accuracy, whereas the other ECUs will suffer considerable errors. Such errors can be a change in slope and/or a displacement or offset of the characteristic curve of voltage against butterfly valve angular position. Such errors in detection do not promote optimum or efficient operation of the internal combustion engine and other functions of the vehicle. The present invention overcomes these problems as set forth in the remainder of the specification and shown in the attached drawings.